Gramec - Mixers

Tens of thousands - maybe millions - of products are manufactured as unique blends of various constituents, and recipes or formulas are often closely-guarded secrets. It follows that precise mixing of all the ingredients in the manufacturing process is of paramount importance.

If the formula calls for a mixture of 2 ingredients - say in a 50/50 or 20/80 ratio, this may not be too difficult, particularly if 47/53 or 15/85 is deemed to be acceptable.

However, if the formula has many ingredients - possibly of widely varying specific weights - and one or more of these are added in a ratio of a few parts per million (ppm), then the quality of the mixing process becomes critical.

For example: 10 parts per milion (not unusual in chemical, feed or pharmaceutical formulations; in fact, often trace elements are added in far smaller quantities) corresponds to a small spoonful into an oildrum or bathtub of material. The quality and effectiveness, ie: the usefulness of the final product, depends on the accuracy with which the minor ingredient(s) has been distributed throughout the final batch. Many types of mixers in general use will not perform, and other types will take an inordinately long time. The Forberg, however, can be expected to give acceptable homogeneity in a matter of ½ - 1minute! Even smaller concentrations will be evenly dispersed in a couple of minutes.

The basis for the high precision mixing is in the unique design of Forberg Mixers. They consist of twin drums with counter rotating rotors fitted with specifically angled paddles. This design, combined with the calculated rotor speed, gives rise to the unique fluidised zone mixing.

Gramec-Forberg Mixers are manufactured in 14 different sizes from nominal 6 litre to nominal 5000 litres. Model number indicates size, ie: F1000 has a nominal volume of 1000 litres. Each model will work effectively between 40% and 140% of nominal filling volume, ie: F1000 can be operated effectively between 400 litres and 1400 litres of material to be mixed. Outside these limits, the machines are less effective.

Gramec-Forberg Mixers are designed for blending of dry materials, but will handle liquid addition with ease.

The standard Gramec-Forberg Mixer operates at low speed and is therefore very gentle so that even fragile constituents (ie: cornflakes) can be mixed. When higher shear is required, we can supply machines with built-in Tulip Mills. These are fast-rotating, angular knives that will chop up lumps and agglomerates which may be present or forming during the mixing process.

Using the same fluidised zone principle as the previous models, but fitted with a rotating drive so that charge and discharge is done through the same opening. When cleaning is necessary between batches, rinse water can be discharged at an angle away from product discharge. CIP (cleaning-in-place) has never been so easy!

Due to the extremely favourable exchange rates of major currencies against the South African Rand, our prices are very competitive in the international market.